Tubeless tires have many advantages over tires that require inner tubes, including greater simplicity, lower weight and lower heat buildup. The wheel rims on certain types of wheels, such as spoked or wire wheels, are generally not sealed and an inner tube is required.
Spoked wheels with pneumatic tires have a variety of applications, including automobiles, motorcycles, bicycles, wheelchairs and baby strollers. Spoked wheels include a hub, spokes and a wheel rim. The spokes are generally connected to the wheel rim with nipples that extend through openings in the wheel rim and screw onto the threaded outer ends of the spokes. Air can leak through the nipple openings in the wheel rim and therefore most prior spoked rims have used tires with inner tubes. In order to use a tubeless tire with a spoked wheel, the openings in the wheel rim must be isolated from the pressurized air chamber of the tire and wheel combination with a fluid impermeable barrier.
Rim strips that protect an inner tube from chafing against the nipple openings and the nipple ends are known. U.S. Pat. No. 1,822,568 to Eger discloses one such rim strip. Such rim strips do not provide a fluid impermeable barrier between the openings in the wheel rim and the pressurized air chamber of the tire and wheel combination.
Molded bands of elastic material that are stretched around a wheel rim have been used to seal spoked wheels. These bands extend across the width of the U shaped channel formed by the flanges of the wheel rim and are held in place by the beads of the tire. These bands may require special wheels. These band may not be compatible with regular tire mounting equipment, and may be torn or dislocated during tire mounting. U.S. Pat. No. 4,108,232 to Simpson, U.S. Pat. No. 4,289,186 to Wilde and U.S. Pat. No. 3,335,778 to Blagden et al. each disclose molded elastic band seals for spoked wheels.
Bands of liquid adhesive, such as curable silicone or molten thermoplastic, that is subsequently cured or hardened, have been used to seal the nipple openings in spoked wheels. These adhesives must be precisely applied with special equipment and special procedures in order to avoid creating an severely unbalanced wheel rim. The bands of liquid adhesive are applied by dripping or spraying onto a rotating wheel rim. The curable adhesives require a cure period, generally six to twenty-four hours. The cured or hardened adhesive band can prevent rotation of the nipples and therefore prevent retentioning of the spokes. U.S. Pat. No. 4,150,854 to Lohmeyer and U.S. Pat. No. 4,305,622 to Mitchell each disclose spoked wheels with thermoplastic bands.
Special spoked wheels have been made for tubeless tires. Some of these wheels have an inner rim with nipple openings and an outer rim without nipple openings. After the nipples are installed in the nipple openings of the inner rim, the outer rim is formed or fastened over the inner rim. These wheels are more complex, require more complex manufacturing equipment and may be heavier than conventional spoked wheels. U.S. Pat. No. 3,008,770 to Mueller discloses a dual rim wheel.